Hydraulic control system



Fel.v 17, 1942.

H. F. LAWRENCE HYDRAULlGA CONTROL SYSTEM originalA Filed March 24, 1937nh x E E vll E D m n TL mm1 n m m m um .v

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I "ctente'd'y Feb. 1942 l IUNITED STATES vorifice HYDRAULIC coNraor.SYSTEM Howard F. Lawrence, Philadelphia, Pa., assigner to American Engineering Company, Philadei.

f phia, Pa., a corporation of Pennsylvania Original application March24, 1937, Serial No:

132,689, now Patent No. 2,221,313, dated November 12, 1940.

Divided and this application May 29, 1940, Serial No. 337,803

` (ci. ca -52) 8 Claims.

This application is a division of mypending application Ser. No.132,689, filed March 24, 193'1, on which Patent No. 2,221,313 wasgranted on November 12, 1940, for Hydraulic control systems, and theinvention herein described relates to hydraulic control systems, andmore particularly to systems employedto reverse the direction ofdischarge of pumps whenthepressure thereby exceeds a predetermineddeveloped value.

One object of the present invention is to provide a generally improved-and simplified control system of the stated character which is fullyautomatic in operation.

Another object is to provide a system of the stated character whereinthepump controls are positively actuated to effect a reversal ofthedischarge therepf. l

A further and more specific object is to provide in a iluid systemincluding a high pressure Ipump for actuating feeding rams, a controlde- Referring to the drawing, thehydraulic cone taken substantially trolsystem comprising'the present invention includes a pump |40 which,'inthe present in\ stance, is adapted to operate a pair of fluid motors|56. The operation of said fluid motors .is controlled by a valve |4|,which in'turnls 'actuated by a control system hereinafter fully de- PumpMu in by an electric motor A|42 through any suitable coupling |43,vFluid is supplied to the system from a makeup or supply tank |44` whichis connected toone side'of the pump -by an intake pipe |45.

Pump v|40 may be vof the general type 'shown in Patent No.l 1,077,979,or any vother suit'- able type and, as shown in Fig. 1, discharges fluidunder pressure into a pipe |46, which pipe is connected to a port' |41"communicating with the k central cylindrical chamber |40 of valve `|41.Valve |'4| has provided therein a pair of spaced the present instance isoperated ports |49 and |50, which ports are connected vrespectively toone end of Vpipes and y|52. Pipes |5| and |52 are connected by branchpipes v|56 and |54, to the opposite ends of the cylinders 5- |55 offluid motors |56. Cylinders |55 have pistons |51 operating therein towhich feeding rams may be connected in any suitable manner. Valve |14|has also provided therein a port |56- at one end thereof which isconnected to makeup tank |44 by means of a pipe |59., The reduced vportions |60 and |6| at the Opposite ends of chamber |48 'are connectedby means of'a pipe |62. Valve |4| has provided therein a valve element'|63 having a p-ir of valve heads |64 and |65 connected'by reducedportion |66. Valve element |63 has a 'stein |61 secured nthereto whichextends through the end wall |66 of valve 4|. The opposite end of valvestem |61 has secured thereto a piston |69 which operates in the cylinder|10 of a iuid motor |1| secured in any suitable manner, such as by bolts|12, to the casing of,valve |4|. The-head end |13 of motor |1|v isconnected to a normally closedI port |14 of va,r

, control valve |15 by means of'apipe |16. The other end of motor |1| isconnected to a secondof the invention proport `,|11 of control valve |15by means of a'second v-pipe |16. Control valve |15 has provided thereina. pair of cylindrical chambers |19 and y|60 which are connected at-oneend there`of by a passage |6| and ports`|62 and |66. Chamber |19 hasprovided therein a vvalve element |64, consisting of a pair of valveheads '|65 and |66 connected by a reduced portion |61, 'I'he upper endof valve element |64 has secured thereto a reduced Vguiding extension|66 which extends through a guiding aperture .|69 provided at theprovided ltherein an adiustablerelief 'valve which in' turn is connectedto makeup tank |44j upper end of control valve |15. Chamber |66also'haspiovided therein a similarly constructed valve-element |90consisting of a pair of valve heads |9| andv |92 connected by a reduced.portion |93. One end of valve |90. also has secured thereto a reducedguiding extension |94 which extends through a'second guidingv aperture|95 in line with chamber |601 The upper end of chamy ber |19 isconnected to-pi e |52 by means of apipe |96. The upper end of chamber isconnected to pipe 5| 'by a pipe |91. Passage |6| is connected to a smallpump-|96 by means of a pipe |99. Pump |98 is connected to theshaft 206of pump |40 by a chain and sprocket mechanism 20|. Fluid is. drawn intopump |96 frommakeup tank |44through a pipe 202. -Pipe |99 las` byvmeanlsof a pipe 204.l Relief valve 203 may be 'of any suitable constructionwhich will open to exhaust when the pressure imposed thereon exceeds apredetermined value, as fully set forth in my above noted Patent No.2,221,313.

The cylindrical chambers |19 and |80 of control valve |15 areinterconnected intermediate the ends thereof by means of atransverselpassage 205. A second passage 206, extending substantially atright-angles to passage 205, extends from the latter to the outside ofthe casing of valve |15, and a. pipe 201 connects passage 206 withmakeup tank |44. Any iiuid leaking past tons |51 reach the limit oftheir travel in this direction, the pressure developed by pump |40 theupper guide portions |88 and |94 of valve members |84 and |90respectively, flows into a vertical passage 208 which extends fromtheupper end of valve |15 to passage 206. It will be observed that whenvalve members |84 and |90 are in their uppermost position, the ports |11and |14 are only partially covered by the valve heads |85 and |9|respectively. `Thus, when valve |90 is in the positionwshown in Fig. 1,and iiuid from pipe |5| flows through pipe |91, port |14 and pipe |16 tothe head end of piston |69;"the iiuid at the other end of cylinder willpass through pipe |18, port |11, the annular cham-- ber between valveheads |85 and |86, transverse causing pump |98 to move valve element |84up- `hand ends of cylinders |55, causing the pistons |51 operatingtherein to move to the'left. The fluid at the left hand end ofcylindersv 55 now iiows to makeup tank as previously described, throughpipes |54, |52; port |50, chamber |48, and pipe |59. As soon as valve|63 is 'shifted to the position shown in Fig. 1, the pressure of thefluid at the upper end of chamber |19 is relieved,

wardly. Fluid at the upper end of chamber |19 will now iiow to makeuptank through pipe |06,

fpipe |52, chamber |48 oi valve |41, andpipe |59.

passage 205, passage 206, and pipe 201, to makeup tank |44. On the otherhand, when'valve |90 is in its upper position, and valve |84 is in itslower position, iiuid from the head end of cylinder |10 will flow tomakeup tank |44 through pipe |16, gport |14, the chamber between valveheads |9| and.|92, transverse passage 205, pas'- sage 206, and pipe 201.

From the foregoing description it is seen' that port |41 of valve |4| atall times is disposed between valve heads Y |64 and parts are in theposition shown in Fig.l 1 fluid from pump |40 enters the central chamber|48 of valve |41 through pipe |46 and port |41. Fluid then flows to theright hand ends 'of cylinders |55 through pipe |5|, causing pistons |51to move to the left. #Fluid at the left hand end of cylinders |55 theniiows to makeup tank through pipes |54, |52, port |50, chamber |48,H

the reduced portion |6| thereof, and pipe |59.

en `pistons |51 reach the limit of their travel in this direction,pressure builds up in pump |40. This pressure is transmitted to theupper end of valve member |90 through pipe |91. When this pressure issuiiicient to overcome that imposed against the lower end of said valvemember by the small pump |98, valve element |90 moves downwardly,thereby uncovering port |14 to pel"- mit iiuid under pressure to enterthe head end of motor |10. Piston |69 of mutor |1| 'now actuates valveelement |66 to its other extreme |85. When the4 This procedure isrepeated to eiect reverse operations of pistons |51 when they reachtheir limit,l

of travel in either direction.

It therefore is seen that a simplified, as well as highly improvedhydraulic control system'has been provided which positively reverses thedischarge of the pump when the pressure in the f system exceeds apredetermined value.

While the embodiment herein shown and described is admirably adapted tofulfill the objects primarily stated, it is to be understood that theinvention is not to be limited thereto, since it may be embodied vinother forms, all coming within the "scope of the' claims which follow.

What is claimed is:

1. In a device of the class described, the combination of a pump, a pairof pipes for alternately .e delivering fluid pressure from said pump, adisposition of adjustment, and thereby establishes communication betweenpump 40 and pipe |52.

Fluid now enters the left hand end of cylinders |55, thereby causing thepistons 51 operating therein to move to the right. The uid at the vrighthand end of cylinders |55 will now ow back to makeup tank through pipes|59, 5 port |49, chamber |48, reduced portion |60, pipe |62, reducedportion |6|, andepipe |59.4 As soon as Dvalve |63 moves downwardly toconnect ports |41'andl50, thereby causing the discharge of pump 40 toenter pipe |52, the pressure at the upper end of valve head |9|isrelieved, and consequently valve |90 -is moved upwardly by thepressure from pump |98. The huid at the upper end of chamber |80 nowpasses to makeup tank through pipes |91 and |5|, port. |49., chamber|48, pipe |82, port |58 andpipe |59. `When pistributing valve forcontrolling the ow of iiuid in said pipes, normally inoperative fluidpressure means for adjusting said valve to different positions ofadjustment, valve means for controlling the operation of said iiuidpressure means, means bination of a ,pump, a pair of pipes foralternately delivering fluid pressure from said pump,

a distributing valve for controlling the ow of fluid in said pipes,normally inoperative iiuid pressure means for adjusting'said valve, avalve mechanism consisting of a pairof valve velements for controllingthe operation of .said fluid preselements with one of said pipes,means'connecting one end of the other of said elements with the ptherofy said pipes, an auxiliary source of fluid pressure, means connectingthe other -end of each of said valve elements to said auxiliary sourceof pressure, whereby when the pressure in either of said pipes imposedupon said valve ele-Y ments exceeds that imposed upon said valveelements by said auxiliary source of fluid pressure` the valve elementsubjected to such pressure ymoves to open the associated discharge portto a distributing valve for controlling the flow of fluid in said pipes,normally inoperative servo motor means operated bythe uid pressuredeveloped in said pump for actuating said distributing valve todifferent positions of adjustment,

a valve mechanism comprising a pair of valveelements for controlling theoperation of said servo motor means, means connecting one end of one ofsaid valve elements to one of said pipes, means connecting one end ofthe other of said valve elements to the other of said pipes, anauxiliary pump, and means connecting the opposite end of each of saidvalve elements to said auxiliary pump, whereby when the pressuredeveloped by said first mentioned pump exceeds that developed by saidauxiliary pump, the valve element subjected to such pressure operates torender said servo motor operative toeffect adjustment of saiddistributing valve.

4. In a device of the class described, the combination of a pump, a pairof pipes for alternately delivering fluid pressure from said pump, adistributing valve for controlling the flow of fluid in said pipes,normally inoperative servo motor means operated by the fluid pressuredeveloped in said pump for actuating said distributing valve todifferent positions of adjustment, a valve meclanism comprising a pairof valve elements for controlling the operation of said servo motormeans, means connecting one end of one of said valve elements to one ofsaid pipes, means connecting one end of the other of said valve elementsto the other of said pipes, an auxiliary pump, means connecting theopposite end of each of said valve elements to said auxiliary pump,whereby when the pressure developed by said first mentioned pump exceedsthat developedrby said auxiliary pump, the valve element subjected tosuch pressure operates to render said servo motor operative to effectadjustment of said distributing valve, and means for varying thepressure developed by said auxiliary Pump.

5. In a device of the class described, the combination of a main pump, adouble-acting fluid motor operated by the said main pump,'meanscontrolling the ilow of iiuid from said pump to said uid motor, normallyinoperative servo motor means for actuating said VAcontrolling means,

the other end of said valve means tothe pressure side of said auxiliarypump whereby when the pressure imposed upon said valve means by saidmain pumpexceeds that imposed thereon by said auxiliary pump. said valvemeans operates to yrender said servo means operative to effectadjustment of said controlling means. 6. In a device of the classdescribed, the combination of a main pump, a fluid motor operated bysaid main pump, a distributing valve for controlling the flow of iiuidfrom said pump to said uid motor, normally inoperative means foradjusting said distributing valve, valve means for controlling theoperation of said normally inoperative means, means connecting one endof said valve means to the pressure side of said main pump, an auxiliarypump, and means connecting the other end of said valve means to thepressure side of said auxiliary pump whereby when the pressure imposedupon said valve means by saidmain pump exceeds that imposed thereon bysaid auxiliary pump said valve means operates to render said normallyinoperative means operative to eiect adjustment of said distributingvalve.

7. In a device of the class described, thecombination of a main pump, afluid motor operated by saidmain pump, a distributing valve forcontrolling' the i'low of fluid from said pump to said fluid motor,normally inoperative means for adjusting said distributing valve, valvemeans for controlling the operation of s aid normally inoperative means,means connecting one end of saidvalve means to the pressure side of saidmain pump, an auxiliary pump, means connecting the other end of saidvalve means to the pressure side of said auxiliary pump whereby when thepressure imposed upon said valve means by said main pump exceeds thatimposed thereon by said auxiliary pump, said valve means operates torender said normally inoperative mally inoperative means, saidvalvemechanism comprising a pair of valve elements, means for alternatelyconnecting one end of each of said valve elements to the pressure sideof said main pump, an auxiliary pump, and means connecting the oppositeend of each of said valve elements to the pressure side of saidauxiliary pump whereby when the pressure imposed upon either valve meansfor controlling the operation of said servo motor, means connecting oneEnd of said valve means to the pressure sideof saidv main pump, anauxiliary pump, and means connecting of 'said valve elements by saidmain pump exceeds that imposed thereon by said auxiliary pump the saidvalve element subjected to such

